Neurofeedback provides the possibility of endogenously manipulating brain activity as an independent variable, and as such provides a novel way to investigate brain function and neuroplasticity. In this talk, I will describe how Electroencephalography (EEG)-based neurofeedback may be deployed in novel experimental and clinical paradigms using multimodal windows on the brain, including fMRI and transcranial magnetic stimulation. Lastly, the neuroplastic effects of neurofeedback will be examined from the theoretical perspectives of Hebbian and homeostatic models of brain plasticity.